Space telegraphy.



PATENTED JAN. 22, 1907.

' f s. CABoT.

SPACE TELEGRAPHY.

ABPLIGATION PILED NOV.25, 1905.

2 SHEETS-SHEET 2.

-NWC J .NL

No/ZYQS. y'PATENTED JAN. 22, 1907.

S. CABOT.

SPACE TELEGRAPHY.

` APPLICATION FILED NOV.25, 1905.

Y 2 SHEETS-SHEET 1.

MfIJEEEES;

UNITED STATES PATENT OEEIOE.

sEwALL-OABOT, OF BROOKLLNE, MASSACHUSETTS, ASSIGNOR TOSTONE TELEeRAPH AND TELEPHONE COMPANY, OE BOSTON, MASSACHU- SETTS, A'OORPORATION OF MAINE. i

SPACE TIELEGRAPH Y.

Specification of Letters Patent.

Patented Jan. 22, 1907.v

Appiimion me@ November 25, 1905. s'erinNo. 288.990.

Aof which the .following'is a specification.

. My invention relates to the art of transmitting intelligence from one station to another by means of electromagnetic waves without the use of wires to guide the waves to their destination; and it relates more particularly to a complete system'for transmitting and receiving such waves.

The object of the present invention is to` provide a system whereby the well-known operation of breaking such as used to-day in wire-telegraph traffic, as worked out in ,duplex and quadruplex systems, may be applied to the handling of wireless-telegraph traffic.

With this object in view my invention' comprises a receiving system connected to a transmitting system at a polnt other than one of zero potential; and it further comprises a key provided with means, 'whereby,` at the commencement of the downward y movement of said key, the receiver is'rendered inoperative and the transmitting system is connected to earth, thereby automatically putting said transmitting system in condition for transmitting; whereby, at the completion of thek downward movement of said key, the said transmitting system is energized; whereby, at the commencement of the upward movement of said key, the transmitting system is denergized; and finally, whereby, subsequently to such denergization the receiving system is put in condition for receiving by disconnecting the transmitting system from earth l and rendering the recelver operatlve.`

For the purpose of more fully disclosing my invention, Ihave illustrated and shall particularly describe one specific. embodiment thereof, although it is to be understood that I do. not limit myself thereto for my invention is capable of-many other embodiments.-

My invention lmay best be understood `by having reference .to the drawings which accompany and forni a part of this specification, and in which the same reference characy ters are used to designate like parts in the figures.

In the drawings, yFigure 1 -is a diagram representing an organization of apparatus and circuits whereby the objects of my invention may be carried into effect and showing in plan view one form of the high-potential switch G; and Fig. 2 is a view identical to Fig.` l

`with respect to the circuits shown therein,l

with the exception that the'relay r has been omitted for clearness, andfshowing the said high-potential switch in end elevation.

In the figures, C C, C2 are condensers.l

L is an inductance-coil.

M is a transformer whose primary and secondary windings I1 and I2 are preferably Vso spatially related as to produce a transformer of large magnetic leakage.v 4The Separation of said windings is herein shown for the sake of clearness as a transverse separation, although in practice the separation is axial.

M is a transformer adaptedto raise the potential impressed upon its mg I1 to a very high potentia ary winding I2.

.M is a transformer whose primary and secondary windings Il" and I2v are referably so spatially related as to pro uce a transformer of large ma netic leakage. Here again the se4 aratlon o? the coils is, for the purpose of c earness, shown as a transverse separationfalthough inpractice the separation is axial; A

.S isa spark-ga E iE are eart connections.

in its second- P is-an oscillation responder or receiver of any suitable type and herein represented merely conventionally by a circle.

K is a key.

A is an alternating-current. generator or other suitable source of power.

G is a high-potential switch hereinafter more fully described.

InV wireless or space telegraphy, asin telegraphy by connecting-wires, it is often desirable for thereceiving operator to interrupt the transmitting operator, that is 'to say, if the receiving operator should fail to get a portion of a message, it is desirable that he should be able to immediately notify the transmitting operator of the fact so that the'latter may repeat that portion of the message which the former failed to get, in-

roo

rimary windstead of having to wait until the transmitting operator has finished sending the message and then notityin him that a portion of the message had not Iieen received.

In wire telegraphy, especially as developed in the practical operation of the duplex 4and quadruplex systems, this is accomplished very simply in a manner well known to those skilled in the art of telegraphy, but in wireless telegraphy the peculiar dlfficulties involved in arrangin the circuit connections in transmittin an .receiving systems, as well as the di erences between said circuit connections, and also the eXtreme sensitiveness of the oscillation-responder renders the operation of breaking more diflicult and, so far as I am advised, no system has yet been devised whereby such o eration may be eifected. In all the embo iments of the present invention, I accomplish the hereinefore-stated objects by means of a sendin key or othersending device provided witi auxiliary apparatusV and circuits whereby the followin functions are performed in the following or er, viz: first, rendering the ososcillation-responder inoperative at vthe beinning of the downstroke of the key land isconnecting the vertical, or elevated conductor perse, from the receiving system to which it normally is connected and connecting the same to the transmitting system; and

` second, closing the power-circuit.

In that particular embodiment of the present invention which I have herein illustrated and which I shall specificall describe for the purpose of more fully disc osing my invention, the receiver or responder isrendered inoperative by opening its circuit by means of a relay, the circuit of said relay being closed by the sending-key, although it is obvious that many-other means may be used for this purpose. By the term rendering the recelver inoperative, as used in the specification and claims, I desire to be understood as meaning an operation whereb the receiver is rendered incapable of pe orming its natural functions, and inasmuch as IA consider any suitable means for accomplishing this result within the scope of` my .invention it is not my intention to limit myself to the particular means which I have shown in the drawings, and furthermore it is to be understood that my invention is not limited to any particular kind of oscillation-responder or to any particular t pe of transmitting or receiving system. the term .sending-key as used herein I esire to be understood as meaning any device whereby the electromagnetic waves are broken up lnto groups representing signal elements such, for example, as the dots and dashes of the Morse code. l

Referring now to Fig. 1, and particularly to the device represented by the character G, 1 is a rod of insulating material mounted pivotally between the supports 4 4. This rod carries' a series of contact members 3 3 the outer ends of which are normally maintained immersed in the mercury contained in the cups 5 by means of the spring which draws the members 3 3 against the back-stop b. As shown in Fig. `2 the rodl carries also the contact-strip 6 which vddjrrates with the mercury in the cup 'Z when the rod 1 is slightly rotated in such direction as to break the connection between the members 3 3 and the cups 5'. Such rotation of the rod 1 may convenient-ly be effected by the magnet m, which is energized by the battery B when the key K ycloses the contact lc. ,The energization of the magnet m causes the armature t to strike the member 2 which is rigidly secured to the rod 1 and thereby` causes a slight rotation of the rod v1 and disconnects the members 3 3 from the cups 5 5 and connects the member 6 with the cup 7.

the circuit may e traced as follows: from the vertical V to thepoint o, through the members 3 3 and the mercu1y-cups-5 to the receiving system and thence to earth at E. The key K being in` its normal position, the contact k is open andthe armatures tt of the relay 1' are normally hold against their cooperating cont-acts so that the circuit oi the receiver is normally closed.l The receiving system therefore is in condition for tion.

When the transmitting operator depresses yhis key, the first operations effected are the closure of the contact lc thereby energizing the relay 1 which, by cai'isingthe attraction of the armatures tgt opens the circuit of the receiver P, and the closure of the contact k, thereby energizing the magnet m, which by causing the attractionv of i's armature t against the tension'of the spring eifects a ofsaidrod disconnects theelevated conductor from the receiving system by raising the contact-strips 3'3 from the cups 5 5 and'connects` said elevated conductor to the transmitting system bv lowering the member 6 intothe cup 7. he closures of the contacts k and k" may be simultaneous lor successive, all that is necessary being. that they occur prior to the closure of the contact k and the consequent energization of the transmittingcircuit. The system is now in condition for transmitting and the further depression of the key eiiects the closureof the contact k and the energilzation of the transformer M. The alternating current thereby` developed in the primary of said transformer is transformed into a high-potential current in the secondary thereof and such current in the usual well-known manner creates high-frequency, high-potential ,electrical oscillations in the sonorous vcircuit S C I1 which bymeans receiving when the key is -in its normal posi- 4 In the normal osition of the sending-key` p IOS slight rotation of the rodi.- Such rotation IIO oi the transformer M are translated to the elevated-conductor system V o I2 E. The aforesaid oscillations will be simple harmonic in form, if as set forthin United States'Letters Patent Nos. 714,832 and 767,984, the windings of the transformer M are so spatially related-as to render the sonorous circuit the equivalent of a circuit having a single degree of freedom. While such relation between the windings of said transformer is preferred, it will be understood that my invention is not limited thereto but is capable of application to any system irrespective of the form of the oscillations developed therein or the ,waves transmitted therefrom. l

It is not deemed necessary to explain in detail the construction, proportionmentor operation of the particular receiving-circuitsherein shown inasmuch as such explanation may be found in United States Letters Patent No. 767,994. Said circuits-are merely shown for`the purpose of more fully illustra'ting this invention as it has been practiced by me and it will be obvious that it is independent of any particular arrangement of receiving-circuit s.

It is well known that., other things being equal, a given difference of potential is required to break down a given length of air or other dielectric, and also that if a given length of dielectric such as air is divided into a number of portions separated by conduc tors, the dielectric strength of said givenlength of dielectric is greatly increased, as more fully set forth in 'United States Letters Patent No. 7 68,000. When the sending-key is depressed and the elevated conduct-or by means of the contact-strip 6 and mercury-cup 7 is connected with the transmitting system, there exists between the point o and the point E', and consequently between the point o and the point E, an enormous difference of potential, large enough in many instances to break down one and one-half inches of air so that were the switch G con'-V structed in the ordinary manner itsswitchl member would necessarily have to be separated from its cooperating contact, such as the mercury-cup V5, a distance slightly greater than one and one-half inches. However, I find in view of the principle above set forth that by using eight switch members, the separation of; each member from its cup being one-sixteenth of an inch, and thereby urproducing one-half inch of air separated by seven metallic bodies, the potential necessary to break down said half-inch of air so disposed is somewhatgreater than that required to break down a gap consisting of one and one-half inches of air.

It will be observed that in the course of sending messages -at even slowrates of speed the vibrations of the contact-strips 3 and 6 must necessarily be very rapid and therefore it would be quite impracticable to emploj' l ght so that the switch will have very small ordinary switch whose contactjnember was capable of the aforesald large movement necessary in view of the large difference of poteni tial between the points o and E, so that, therefore, in order to alternately connect the elevated conductor to the transmitting and receiving systems by the sending-key it is necessary to employ a switch which willhave a verya small range of movement and which notwithstanding said small range of movement will prevent the breaking down of the dielectric between its contact members.. 'It will further be observed that the moving parts of the switch G must be extremely inertia in order to permit of the rapid'vibration thereof.

After the operator has depressed the sending-key to its full extent for a sufficient length of time to produce' the desired signal element, the key is allowed to regain its normal position and the following cycle of o erations isl eected.: First, the contact il is opened thereby denergizing the transformer Y M; and, second, the contacts k and k are opened an appreciable interval of time after t aforesaid e opening of the contact k.- When the'y contact'c is opened the magnet m is denerized, its armature t is retracted against its ack-stopt by the s ring and the switch Z is rot-ated slightly a out itsjpivots by the spring m until its contact members 3 3 are brought against-their back-stops b and are immersed in the mercuryl of the cupsI 5. 5, thereby disconnecting the elevated conductor from the transmitting system and connecting it to the receiving syst-em. When'the contact kf is opened the relay r is denergized and the circuit of the receiver is closed by the action of the springs x on the armatures tt. It will be understood of course that instead of opening the circuit of the receiver'at two points, asingle armature Lt may be used to open it at one point. The contacts c and 7c may beopened simultaneously or successively.- Y

An appreciable interval of time must of course elapse between the sending of signal elements', and it isduring such intervals of time when the key K is in its normal position that -the sending operator, b means of the receiver P or the usual loca circuit which may be associated therewith, may ascertain that the receiving operator at the distant vstation is signaling breakff Said receiving o erator having failed to receive a portion of t e message transmitted tohis station, depresses his sending-key immediately upon such failure to receive a Word or portion of the message and sends a predetermined sig- 'nal indicating that he wishesthe transmission stopped. The waves sent out by said receiving operator develop in the vertical at the -station from which the message is'being sent to said receiving operatorelectrical oscilla- IOO tions which, during the interval ofl time between the signal elements when the key is in its normal position, pass to earth E by way of the receiving system and so produce indications in the signal indicating device. Such signal indications tell the. transmitting operator that the receiving operator is signale ing brealc and he thereupon ceases his transmission and receivesfrom the receiving operator instructions concerning` the repetition desired by the latter.

Although for the purpose of more clearly disclosing rey invention lhave speciiically described one forni of high-potential switch and one arrangement of transn'iitting and receiving systems, it will be understoed that I do not limit myself thereto inasmuch as many modifications may be made therein without departing from the spirit of my in- -vention. l

I claim- 1. ln a space-telegraph system, a transmit-ting system, a receiving system, an elevated conductor, a sending-key, ahirh-potential switch constructed and arranged to alternately connect said elevated 4conductor to said transmit-ting,T and ,receiving systems, said switch comprisingr means for augmentingT the ap in the circuit beyond an air-gap formed between two contacts, and means controlled switch.

2. ln a space-telegraph system, a transmitting system, a receiving system, an elevated conductor, a sending-key, l a switch comprisingT a number of series contact members constructed and arranged to alternately connect said elevated conductor to said transmitting and receiving systems, and means controlled by said sending-key for operating said switch.

3. In a space-telegraph system, a transy mitting system, a receivine system,` an elel vated conductor, a sending-hey, a switch normally connecting said elevated conductor to said reeeivil'ig system through a number of series cont act members, a contact carried by said switch constructed and arranged normally to disconnect said elevated conductor from said transmitting' system, and means controlled by said sending-key for operatingr said switch.

ln testimony whereof i have hereunto subscribed my name this '22d day of November,

1 by said sending-key for operating said SEVVALL CABOT.

FRANK ('ff. BLAISDELL,

t Witnesses 1 GEO. Ix. W ooDwoRTn. 

